Experimental investigation of a modular helix-acoustic black hole

To overcome the manufacturability and safety issues of the conventional acoustic black hole (ABH), a modular type ABH structure was proposed, consisting of several conventional ABH beams and a base structure that can be attached to its surface. To improve the performance of the modular ABH structure, a new type of beam, a helixacoustic black hole (h-ABH), was used. The new ABH structure, which comprised a number of h-ABH parts and a circular base was evaluated in terms of the reflection coefficient and damping performance when attached to a rectangular plate. The experimental results showed that the reflection coefficients of the h-ABH beam decreased over the entire frequency range, regardless of the excitation direction. For the modular h-ABH (mh-ABH) system showed significant reductions at resonance frequencies compared with the reference bare plate. Our results demonstrate the effectiveness of the mh-ABH structure for minimizing damping effects in practical structures.

Automated summary

This article proposes a modular acoustic black hole (ABH) structure with a helixacoustic black hole (h-ABH) beam to improve its performance. Experimental results show that the reflection coefficients of the h-ABH beam decrease over the entire frequency range and the modular h-ABH system significantly reduces resonance frequencies and damping effects.